[FFmpeg-devel] [PATCH 4/5] avformat/mxfdec: fix data_essence_descriptor matching logic

[Tomas Härdin]

mån 2018-05-28 klockan 00:16 +0200 skrev Marton Balint:
> 
> On Sun, 27 May 2018, Tomas Härdin wrote:
> 
> > sön 2018-05-27 klockan 21:21 +0200 skrev Marton Balint:
> > > > Signed-off-by: Marton Balint <cus at passwd.hu>
> > > 
> > > ---
> > >  libavformat/mxfdec.c | 10 +++++-----
> > >  1 file changed, 5 insertions(+), 5 deletions(-)
> > > 
> > > diff --git a/libavformat/mxfdec.c b/libavformat/mxfdec.c
> > > index bd46572e48..a62021b0d7 100644
> > > --- a/libavformat/mxfdec.c
> > > +++ b/libavformat/mxfdec.c
> > > @@ -2354,12 +2354,12 @@ static int
> > > mxf_parse_structural_metadata(MXFContext *mxf)
> > >                  st->need_parsing = AVSTREAM_PARSE_FULL;
> > >              }
> > >          } else if (st->codecpar->codec_type ==
> > > AVMEDIA_TYPE_DATA) {
> > > -            int codec_id =
> > > mxf_get_codec_ul(mxf_data_essence_container_uls,
> > > -                                            essence_container_ul
> > > )->id;
> > > -            if (codec_id >= 0 &&
> > > -                codec_id <
> > > FF_ARRAY_ELEMS(mxf_data_essence_descriptor)) {
> > > +            int index;
> > > +            container_ul =
> > > mxf_get_codec_ul(mxf_data_essence_container_uls,
> > > essence_container_ul);
> > > +            index = container_ul -
> > > mxf_data_essence_container_uls;
> > 
> > Nice use of C peculiarities (:
> 
> The other way is to add a char* to the MXFCodecUL struct, but I
> thought 
> that would be overkill for such a tiny use case.
> 
> > 
> > > +            if (index <
> > > FF_ARRAY_ELEMS(mxf_data_essence_descriptor)) {
> > 
> > index can never be <0? Say if container_ul == NULL...
> 
> No, because mxf_get_codec_ul never returns NULL.

Alright, looks OK then. Still irked by the lack of static analysis.
Maybe should give Frama-C a go in some module one day

/Tomas